AGE-RELATED DECLINE IN CENTRAL CHOLINERGIC FUNCTION DEMONSTRATED WITHSCOPOLAMINE

Scopolamine hydrobromide was administered intravenously to 23 normal s ubjects (40-89 years) in doses of 0.1 mg, 0.25 mg, and 0.5 mg, in a do uble-blind, placebo-controlled, random-order fashion, The effects of s copolamine, as compared to placebo, were assessed using a comprehensiv e cognitive test battery, as well as behavioral and physiological meas ures. Scopolamine produced the expected dose-dependent impairments in most of the cognitive functions assessed. Behavioral and physiological measures were also affected, but only minimally. More importantly, th ere was a significant overall correlation between age and scopolamine- impaired performances on psychomotor speed, short-term recall, visual tracking speed, visuo-motor coordination, and sequencing ability. Ther e was, however, some inter-individual variability in this phenomenon. The results provide further evidence that cholinergically mediated cog nitive functions show an increased sensitivity to scopolamine with age , albeit with heterogeneity that bears further investigation.